From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- net/dsa/trace.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 net/dsa/trace.c (limited to 'net/dsa/trace.c') diff --git a/net/dsa/trace.c b/net/dsa/trace.c new file mode 100644 index 000000000..1b107165d --- /dev/null +++ b/net/dsa/trace.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Copyright 2022-2023 NXP + */ + +#define CREATE_TRACE_POINTS +#include "trace.h" + +void dsa_db_print(const struct dsa_db *db, char buf[DSA_DB_BUFSIZ]) +{ + switch (db->type) { + case DSA_DB_PORT: + sprintf(buf, "port %s", db->dp->name); + break; + case DSA_DB_LAG: + sprintf(buf, "lag %s id %d", db->lag.dev->name, db->lag.id); + break; + case DSA_DB_BRIDGE: + sprintf(buf, "bridge %s num %d", db->bridge.dev->name, + db->bridge.num); + break; + default: + sprintf(buf, "unknown"); + break; + } +} + +const char *dsa_port_kind(const struct dsa_port *dp) +{ + switch (dp->type) { + case DSA_PORT_TYPE_USER: + return "user"; + case DSA_PORT_TYPE_CPU: + return "cpu"; + case DSA_PORT_TYPE_DSA: + return "dsa"; + default: + return "unused"; + } +} -- cgit v1.3.1